Although endosulfan is forbidden in over 60 countries, in large
regions of the world, particularly in the southern hemisphere, it is
still used. Technical grade endosulfan (TGE) is commercially available
as a mixture of two diastereomers, known as -endosulfan
(or I) and -endosulfan (or II) in ratios from 2:1 to 7:3. In most
of the brands, the formulation is a mixture of the active diastereomers
(95%) and inert ingredients (5%) [2]. Although there are not
systematic data, the occurrence of endosulfan has been reported
for punctual areas in Argentina before its prohibition in 2013. For
example, in 2012, Gonzalez et al. reported levels of endosulfan
between 0.10 to 1.15 ng L−1 in ground waters of La Pampa [3].
Concentrations of 0.2–13.5 g L−1 were detected in Esteros del
Ibera surface waters [4], while other authors reported quantities
between 0.2 to 35.2 ng of endosulfan per gram of soil in the Patagonia
[5].